Trigger mechanism

ABSTRACT

The invention relates to the field of gun technology. The trigger mechanism comprises a body, a spring-loaded sear, a trigger with a spring, and adjustment screws, including a screw for adjusting the triggering and a screw for adjusting the triggering motion. The trigger mechanism additionally comprises a screw for adjusting the amount of engagement of the trigger with the sear. All of the adjustment screws are mounted in the body and are oriented vertically. The sear is provided with a tooth which can come into contact with a moth present on the trigger. Furthermore, the trigger tooth surface which interacts with the sear tooth surface is curvilinear. The technical result consists in increasing the reliability and simplicity of assembling and servicing the device.

FIELD OF THE INVENTION

The invention relates to weapon technology area, particularly to trigger mechanisms of arms having lengthwise sliding bolts, for example, for hunting rifles.

BACKGROUND OF THE INVENTION

It is known the trigger mechanism for the BK-5 rifle described by V. I. Trofimov in his guide “Russian Combined Hunting and Sporting Guns”/Part 2.—Moscow: DAIRS, 2000, p. 140. The mechanism comprises a body, a sear with a latch and a sear lever, a triggering lever, and a trigger, and also adjustment screws. The prior art mechanism is complicated in design and, besides, it does not separate the striker and the sear reliably, for which reason the safety of the rifle decreases.

The closest related prior art of this invention is the trigger mechanism disclosed in Russian Patent No. 2219459, F41A 19/24 published on Dec. 20, 2003 that comprises a body, a spring-loaded sear, a trigger with a spring, and adjustment screws; the sear and the trigger in that mechanism have threaded holes to receive the adjustment screws.

Presence of the said threaded holes in the trigger imposes a limit on technology capability in manufacturing of the trigger and necessitates for additional components, typically a special-purpose hard insertion, to be used.

The deficiencies of the mechanism in accordance with the aforesaid patent are primarily its complex design that affects the quality and reliability of the trigger mechanism in operation.

The design of the claimed trigger mechanism is aimed to improve reliability of the trigger mechanism, to expand opportunities for adjusting the release triggering mode and improve the triggering quality, while simplifying the trigger mechanism construction, ensure its manufacturability, simplicity of assembling and servicing the device.

SUMMARY OF THE INVENTION

The above objects are achieved in the trigger mechanism comprising a body, a spring-loaded sear, a trigger with a spring, and adjustment screws, including a screw for adjusting the triggering and a screw for adjusting the triggering motion, said trigger mechanism further comprising a screw for adjusting the amount of engagement of the trigger with the sear, at that all the adjustment screws are mounted in the body and are oriented vertically, the sear is provided with a tooth which can come into engagement with a tooth present on the trigger, and the trigger tooth surface which interacts with the sear tooth surface is curvilinear.

Vertical orientation of the screws means that the screws extend at an angle of 90° to the horizontal axis. The amount of engagement of the trigger with the sear assumes a value (area) of the contact between the surfaces of sear and trigger teeth.

In a particular embodiment, the claimed trigger mechanism may have a technological hole to provide for visual observation of the amount of engagement between the trigger and the sear.

In one embodiment of the invention, the screw for adjusting the amount of engagement of the trigger and the sear and the screw for adjusting the triggering motion are mounted in the body base.

In another embodiment, the curvilinear surface of the trigger tooth, which interacts with the sear tooth surface at the time as the trigger mechanism is in cocked position, has a convex arcuated shape with a curvature radius (R) of 5 to 8 mm.

These design specifics of the claimed trigger mechanism make for reliable and safe operation of the mechanism by higher quality of release triggering because of broader abilities for adjusting the triggering point. The claimed trigger mechanism is easy to manufacture and simple to assemble and provide maintenance services on.

These improvements derive from the possibility of control the amount of engagement between the sear and trigger teeth and exception a possibility of contact between the sharp edge of the trigger tooth and the flat surface of the sear tooth because of the curved surface under the trigger tooth with a curvature radius of 5 to 8 mm. As a result, a possibility of jamming of the sear and trigger at cocked position of the trigger mechanism is practically obviated and a possibility of unintended triggering in case of an insignificant pressure to the trigger is minimized in the claimed trigger mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

The essence of the invention is illustrated by the following drawings:

FIG. 1 is a longitudinal sectional view of the trigger mechanism in the cocked position.

FIG. 2 shows the relative position of the sear and trigger teeth in engagement in phase of cocked trigger mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

As shown in FIG. 1, the trigger mechanism in accordance with the preferred embodiment of the invention comprises a body 1 having an aluminum cover (not shown), a technological hole 2, a trigger 3, a sear 4, a triggering spring 5, a sear spring 6, a screw for adjusting triggering 7, a screw for adjusting amount of engagement of the trigger with the sear 8, and a screw for adjusting triggering motion 9.

Adjustment screws 7, 8, and 9 are mounted in the body base and are oriented vertically at an angle of 90° to the horizontal axis thereof. The sear 4 has a tooth is provided with a tooth which can come into contact with a tooth present on the trigger 3.

The trigger tooth surface, which interacts with the sear tooth surface at the time of cocked trigger, is curvilinear, in particular, as shown in FIG. 2, it is a convex arcuated surface of a curvature radius (R) between 5 and 8 mm.

The amount of engagement is the area of interaction of the teeth surfaces of sear 6 and trigger 3.

The technological hole 2 makes possibility to observe the amount of the engagement between trigger 3 and sear 6 visually.

The claimed trigger mechanism is operated as follows:

To fire a shot, the shooter pulls trigger 3 that turns about its axis to be disengaged from sear 4. In its turn, sear 4 is pushed by the striker down and compresses sear spring 6. The striker disengages from the tooth of sear 6 and moves forcefully forward. After the shot, the striker returns to its previous position. When it reaches its extreme outward position, sear 4 is forced by the spring 6 (loading art arm of sear 4) to return to its initial position of engagement with the striker. Trigger 3 is forced b the triggering spring 5 to return to its initial position as well.

Adjustment of the trigger mechanism is carried out by adjustment screws 7, 8, and 9.

The trigger tension is adjusted by turning screw 7 that either tightens or releases the triggering spring 5. The adjustment range is between 500 and 900 grams in “varmint” gun option and, where more tight spring is used, 1,000 to 1,500 grams in the hunting gun option. A hole is provided in trigger 3 for adjusting the position of screw 7 by a hexagonal wrench.

The amount of engagement of trigger 3 is adjusted by turning screw 8 and can be observed visually through the aperture 2. Trigger 3 by force of the triggering spring 5 set against screw 8 and is in permanent contact therewith. Screw 8 can be used to adjust the point where trigger 3 begins to turn. Trigger 3 is in engagement with sear 4. Change in the point where trigger 3 begins to turn causes a change in the amount of engagement between trigger 3 and sear 6.

Adjustment limit the triggering motion is carried out by turning screw 9. By rotating the screw 9 either decrease OF an increase in the interval move of trigger occurs after disengagement with the sear 6. Such adjustment helps to control the moment of shot more precisely and improves convenience and accuracy of shooting.

All the described processes of adjustment of screws position may be accomplished by hexagonal wrenches without disassembling of the rifle. It can be achieved owing to the screws are accessible from the outer surface of the body.

The claimed trigger mechanism reduces to a minimum the possibility of an unintended shot being fired by an insignificant pressure applied to the trigger because the release effort can he adjusted and the trigger balanced. Besides, it virtually eliminates the possibility of jamming of the sear and trigger at the time when trigger mechanism is cocked because at the same time the shutter mainspring and the sear mainspring are both operate to disengage the sear and trigger. Furthermore, the shape of the friction surfaces of the sear and trigger prevents contact between the sharp edge of the trigger tooth and the flat surface of the sear tooth. The curved arcuated surface under the trigger tooth that, in accordance with this invention, has a curvature radius of 5 to 8 mm reduces friction upon contact between the surfaces of the sear and trigger teeth. The insignificant force (0.8 kgf) of the sear spring has not influence on firearm cocking.

The trigger mechanism of this invention is simple to assemble, has a high quality, and is reliable in use.

INDUSTRIAL APPLICABILITY

The claimed trigger mechanism can be manufactured by standard modern technologies with the use of common materials and it is suitable for use in non-automatic self-loading firearms. 

What is claimed is:
 1. A trigger mechanism, comprising: a body, a spring-loaded sear, a trigger with a spring, and adjustment screws, including a screw for adjusting the triggering and a screw for adjusting the triggering motion, said trigger mechanism further having a screw for adjusting an amount of an engagement of the trigger with the sear, all adjustment screws are mounted in the body of the trigger mechanism and are oriented vertically; said sear is provided with a tooth which comes into the engagement with a tooth of the triggers, and the trigger tooth surface, which at the time of cocking of trigger interacts with the sear tooth surface, is curvilinear.
 2. The trigger mechanism of claim 1, wherein said body is provided with a technological hole permitting visual control of the amount of engagement of the trigger with the sear.
 3. The trigger mechanism of claim 2, wherein said screw for adjusting of the amount of engagement of the trigger with the sear and the screw for adjusting of the triggering motion are mounted in the body base.
 4. The trigger mechanism of claim 1, wherein said curvilinear surface of the trigger tooth is a curved arcuated surface having a curvature radius of 5 to 8 mm.
 4. The trigger mechanism of claim 1, wherein said screw for adjusting of the amount of engagement of the trigger with the sear and the screw for adjusting of the triggering motion are mounted in the body base. 